Heater for use in an electrical smoking system

Abstract

A provided heater comprises a supporting hub and a plurality of electrically resistive heater blades defining a receptacle to receive an inserted cigarette. Each blade comprises a first heater blade leg having a first end and a second end and extending at the first end from the supporting hub, a second heater blade leg having a first end and a second end, and a connecting section connecting the second end of the first leg and the first end of the second leg. The second end of the second leg extends toward the supporting hub and is electrically insulated therefrom. A resistive heating circuit is formed to heat the electrically resistive heater blade which in turn heats the inserted cigarette. The first and second legs are separated by a gap to permit entrainment of flavor substances into the heated cigarette upon drawing by a smoker.

We claim: 
     
       1. A heater for use in a smoking system having a source of electrical energy for heating a cigarette, the heater comprising: a plurality of electrically resistive heater blades defining a receptacle to receive an inserted cigarette and extending alongside the inserted cigarette, each blade comprising a first heater blade leg having a first end and a second end, a second heater blade leg having a first end and a second end, and a connecting section comprising a connecting edge section connecting the second end of said first heater blade leg and the first end of said second heater blade leg;   wherein said first and second heater blade legs of each heater blade are separated by a respective gap; and   wherein the first ends of each first heater blade leg are in electrical contact with the source of electrical energy, wherein respective resistive heating paths are formed comprising said first heater blade leg, said connecting edge section, and said second heater blade leg to respectively heat each of said electrically resistive heater blades, which in turn heats the inserted cigarette.   
     
     
       2. The heater according to claim 1, wherein the second ends of said second heater blade legs are grounded. 
     
     
       3. The heater according to claim 1, wherein the second ends of said second heater blade legs are connected in common. 
     
     
       4. The heater according to claim 1, wherein the second ends of said second heater blade legs are connected in common to ground. 
     
     
       5. The heater according to claim 1, wherein the gap separating said first and second heater blade legs is of sufficient size to permit entrainment of air flow into the heated cigarette upon drawing by a smoker. 
     
     
       6. The heater according to claim 1, further comprising a supporting hub, the first ends of each of said first heater blade legs extending from said supporting hub; wherein said supporting hub is in electrical contact with the source of electrical energy to form a common for the first ends of said first heater blade legs.   
     
     
       7. The heater according to claim 6, wherein the second ends of said second heater blade legs are in respective electrical contact with the source of electrical energy, wherein respective resistive heating circuits are formed comprising said first heater blade leg, said connecting edge section, and said second heater blade leg to respectively heat each of said electrically resistive heater blades, which in turn heats the inserted cigarette. 
     
     
       8. The heater according to claim 6, wherein the second ends of said second heater blade legs extend toward said supporting hub and are electrically insulated therefrom. 
     
     
       9. The heater according to claim 6, wherein the second ends of said second heater blade leg is separated from said hub by a gap. 
     
     
       10. The heater according to claim 6, further comprising an electrical insulator applied to at least one of said hub and the second ends of said second heater blade legs. 
     
     
       11. The heater according to claim 6, further comprising an electrical insulator applied to at least one of the second ends of said second heater blade legs and the first ends of said first heater blade legs. 
     
     
       12. The heater according to claim 6, further comprising an electrical insulator forming a ceramic hub support structure around said supporting hub, the second ends of said second heater blade legs and the first ends of said first heater blade legs. 
     
     
       13. The heater according to claim 6, wherein the supporting hub and blades are monolithic. 
     
     
       14. The heater according to claim 1, wherein said connecting section further comprises a free end to compensate for thermal expansion when the heater element is heated. 
     
     
       15. The heater according to claim 14, further comprising a support structure stationarily located within the smoking system and defining channels to receive the free ends of said connecting sections of said blades. 
     
     
       16. The heater according to claim 14, wherein said channels are sized to permit translational thermal expansion and contraction of said heater blades. 
     
     
       17. The heater according to claim 14, further comprising a pivot point located in each of said channels, said pivot point located such that the associated free end of said connecting section pivots about said pivot point to bias said first and second heater blade legs inward toward the inserted cigarette upon heating of the associated heater blade. 
     
     
       18. The heater according to claim 1, wherein portions of at least one of said first heater blade leg and said heater blade leg are coated with a ceramic to strengthen and electrically insulate the at least one of said first heater blade leg and said heater blade leg. 
     
     
       19. The heater according to claim 18, wherein a portion of said second heater blade leg adjacent said ceramic is in electrical contact with the source of electrical energy. 
     
     
       20. The heater according to claim 1, wherein said blades are arranged to slidingly receive the inserted cigarette. 
     
     
       21. The heater according to claim 1, wherein said blades are shaped to define as insertion opening having an internal diameter greater than the defined receptacle for receiving the inserted cigarette. 
     
     
       22. The heater according to claim 21, wherein said blades further define a throat section between said insertion opening and the defined receptacle, said throat section having a gradually decreasing diameter from said insertion opening to the defined receptacle. 
     
     
       23. The heater according to claim 1, wherein the second end of said second heater blade leg is a step shape, said step shape comprising an end section adapted to be in electrical contact with the source of electrical energy. 
     
     
       24. The heater according to claim 1, wherein said first and second heater blade legs of a respective heater blade are substantially parallel. 
     
     
       25. The heater according to claim 1, wherein said connecting edge has a curvature between approximately 160° and 200°. 
     
     
       26. The heater according to claim 1, wherein an underside of at least one of said first and second heater blade legs facing the inserted cigarette is substantially non-planar in a transverse direction of said heater blade leg. 
     
     
       27. The heater according to claim 26, wherein said underside is curved. 
     
     
       28. The heater according to claim 26, wherein said underside is angled. 
     
     
       29. The heater according to claim 1, wherein said plurality of electrically resistive heater blades are arranged in groups, wherein gaps between the groups are sized to provide unheated portions of the inserted cigarette providing strength to facilitate removal of the cigarette after smoking. 
     
     
       30. The heater according to claim 1, wherein at least one of said first and second heater blade legs is serpentine shaped. 
     
     
       31. The heater according to claim 1, wherein the first end of said first heater blade leg of at least one blade is wider than an adjacent active portion of said first heater blade leg, wherein the first end of said first heater blade leg has a lower current density and a lower ohmic heater than the active portion of said first heater blade leg. 
     
     
       32. The heater according to claim 1, wherein the second end of said second heater blade leg of at least one blade is wider than an adjacent active portion of said second heater blade leg, wherein the second end of said second heater blade leg has a lower current density and a lower ohmic heating than said active portion of said second heater blade leg. 
     
     
       33. The heater according to claim 1, wherein said connecting section further comprises a remainder section having a larger volume than said connecting edge section to have a lower current density and lower ohmic heating than said connecting edge section. 
     
     
       34. The heater according to claim 33, wherein the remainder section of said connecting section is thicker than said connecting edge section to reduce current density and ohmic heating of said connecting section. 
     
     
       35. The heater according to claim 33, further comprising a heat sink communicating with said connecting section. 
     
     
       36. The heater according to claim 1, wherein said connecting section is perforated. 
     
     
       37. The heater according to claim 1, wherein said first and second heater blade legs are biased inwardly toward the inserted cigarette. 
     
     
       38. The heater according to claim 1, wherein said first and said second heater blade legs and said connecting edges have a resistance of approximately 100 to approximately 200 μohm.cm. 
     
     
       39. The heater according to claim 1, wherein said first and said second heater blade legs and said connecting edges have a resistance of approximately 50 to approximately 500 μohm.cm. 
     
     
       40. The heater according to claim 1, wherein said first and second heater blade legs and said connecting edges form an electrical path of such resistance such that, upon pulsing, the legs and edges reach temperatures of approximately 200° C. to approximately 1000° C. in approximately 0.2 to approximately 2.0 sec. with a pulse of approximately 10 to approximately 50 Joules. 
     
     
       41. The heater according to claim 40, wherein said first and second legs and said connecting edges form a resistance heating element of sufficient physical strength such that the resistance heating element is capable of being pulsed to these temperatures approximately 1800 to approximately 10,000 such pulses without failure. 
     
     
       42. The heater according to claim 1, wherein said first and second heater blade legs and said connecting edge sections comprise an electrically resistive material selected from the group consisting of iron aluminides and nickel aluminides. 
     
     
       43. A heater for use in a smoking system having a source of electrical energy for heating a cigarette, the heater comprising: a plurality of electrically resistive heater blades, each blade comprising a first heater blade leg having a first end and a second end, a second heater blade leg having a first end and a second end, and a connecting section comprising an electrically conductive section connecting the second end of said first heater blade leg and the first end of said second heater blade leg;   wherein said first and second heater blade legs are parallel, serpentine, and are separated by a respective gap; and   wherein the first ends of said first heater blade leg are in electrical contact with the source of electrical energy, wherein respective resistive heating paths are formed comprising said first heater blade leg, said connecting edge section, and said second heater blade leg to respectively heat each of said electrically resistive heater blades, which in turn heats the inserted cigarette.   
     
     
       44. A heater as claimed in claim 43, wherein the gap between the first and second heater blade legs is an even space between said legs and is serpentine shaped.